Frequently during surgery, tissue biopsy samples may be removed from a patient and sent from the operating room to a pathology laboratory for analysis, for example by frozen tissue section diagnosis. In addition, methodology for frozen tissue section diagnosis may consist of freezing tissue in a pathology lab, sectioning the frozen tissue, and performing standard Hematoxylin and Eosin (H&E) staining. H&E may be a general-purpose stain for helping a medical pathologist diagnose tissue pathologies. However, H&E staining may have a number of limitations, for example that it may be a non-specific tissue stain, and may not identify specific proteins in tissue. Such identification of specific proteins in tissue, for example by using a procedure sometimes referred to as immunohistochemistry (IHC), may help a pathologist diagnose numerous intraoperative tissue pathologies. Examples may include sentinel lymph node biopsies (for potential metastatic carcinomas and melanomas), undifferentiated tumors (potential carcinomas, lymphomas, and melanomas), and biopsies of margins (looking at the edges of excised tissue to see if the entire tumor has been removed).
A problem may be that current automated IHC may require 60 to 120 minutes, which may be too long to be useful during intraoperative procedures. Intraoperative guidelines, such as those provided by the College of American Pathologists, may typically recommend reporting pathology data to the surgeon within approximately 20 minutes. Another problem is that different reagents need to be used with different tests. Operators can sometimes make mistakes and so a simplified manner of operation is desired.
It often may be difficult to examine unstained cell and tissue preparations with a microscope, for example perhaps due to a lack of contrast between individual cells and the background matrix, or perhaps between individual parts of cells. To improve such contrast, researchers may apply stains to cell and tissue specimens to be examined. Such stains may be adsorbed differently by various structures in cells, perhaps such that the contrast between the different cell structures may be improved.
Staining tissue specimens may be a nontrivial, time-consuming process. Often, a number of different staining and rinsing stages may be required. Each stage may require a specific amount and perhaps different types of reagent or buffer and may take a specific amount of time. Furthermore, at the completion of a test sequence removed material can be a hazardous material that requires specific handling and disposal. Thus, trained technicians often may be employed to perform such operations. Furthermore, hospitals and laboratories may be required to stain large numbers of tissue specimens with different reagents or substances. Thus, it may be desirable to automate the tissue specimen staining process and to make insertion of desired substances easier and more foolproof. By automating the process, expensive human labor may be eliminated and the probability of an error occurring during the staining process may be reduced. Accordingly, some manufacturers have introduced equipment for the automated staining of tissue specimens on microscope slides.
However, existing automatic staining devices may not be simple to use. Such existing automatic staining devices may required arcane programming commands and complicated procedures, which may require extensive user training before such devices can be operated effectively. Waste material can also require special handling. It therefore may be desirable to simplify the operation of an automatic staining device as well as its set up and clean up.
As mentioned earlier, though, existing automatic staining devices can take a significant amount of time to achieve a desired result. When using interacting or perhaps binding substances, such as antibodies, or more generally reagents, the substance used that may take a significant period of time to achieve its chemical result relative to an intraoperative procedure. For example, a typical reagent binding profile using an accelerated incubation period can take in excess of 60 minutes or the like. This is usually too long to leave a patient exposed and so it is not uncommon for the patient to be sewn back up and asked to return once results are available. Furthermore it may not be practical to run a bulk processing system for only one or two samples. While this testing time period may be necessary in order to achieve an amount of binding or other interaction desired with most substances, such a period of time is not typically acceptable from the perspective of performing an intraoperative procedure on a patient. Beyond merely the chemical interaction time period, the entire process can take even significantly longer. Thus it is not uncommon for many staining or other biochemical procedures to require at least one hour in order to yield the desired results.
Furthermore, the entire process may be fairly involved. For example, a biochemical process can sometimes involve steps including: subjecting a sample to a first antibody substance, perhaps driving the antibody substance around with an air knife to blow air across the surface of the sample, withdrawing the antibody substance, rinsing the sample with a buffer, subjecting the sample to a second antibody substance, perhaps again driving the antibody substance around with an air knife, withdrawing the second antibody substance, again rinsing the sample with a buffer, subjecting the sample to a chromogen substance, withdrawing the chromogen substance, again rinsing the sample with a buffer, subjecting the sample to a counterstain, withdrawing the counterstain, and then perhaps again rinsing the sample with a buffer. Each of these steps may take a significant amount of time in and of themselves, and may result in the sum of the entire procedure taking an inordinate amount of time. In fact, it may not be uncommon for such involved procedures to take 90 minutes or more. Although there may have been efforts to shorten this time period, the simple fact of the chemistry involved may have focused these efforts to some degree on speeding up the mechanical processes involved.
One process which may be known to speed up the chemical process, however, is to heat a sample and the substance applied. In this type of a system, a reagent may be heated and this may reduce the reagent-tissue interaction period. Disadvantages to heating may include the fact that many reagents and some samples may not react well to heating.
While the use of an air knife to blow air across the surface of a reagent and to drive the reagent or other substance around on the surface of the sample may have accomplished some shortening of the overall process, it remains a fact that even when this function is employed, the procedures still require long time periods on the order to 60 to 120 minutes. Thus, one of the challenges and one of the limitations of many of the automated histochemical and other such systems previously in use is the fact that they simply do not yield their results in a short enough time period in order to provide systems that can be used effectively in an intraoperative environment. Prior to the present invention, it may have even been perceived as a necessary incident to the basic chemistry that such tests required this long a time frame. In view of the foregoing, there is a need for the availability of an automated rapid IHC or other such system that would allow IHC or the like to be performed within 20 minutes or less. Automated rapid IHC or other such biochemical tests are, of course, also desired by research laboratories for frozen tissues and the like.